The invention relates to a golf club device, more specifically a so-called putter, which is used to hit the golf ball the last distance to a hole.
A putter is used in order to hit a golf ball a relatively short distance, typically from a few millimeters to about thirty meters. The putter is arranged with a club face, which is nearly perpendicular relative to the ground surface when the putter hits the ball, in order for the ball to roll along the ground.
Golf clubs that are used in competition, must have a configuration in accordance with the rules that apply to the game of golf. Technical solutions are known, which may help the player to achieve optimal strokes, but the set of rules allows limited freedom of action in terms of technical means.
Known optimization of golf clubs includes variations in the angle of the club face, the mass and shape of the club head, the mass, shape and rigidity of the shaft, the position of the center of gravity of the club head relative to the position of the shaft attachment and the point where the face is to hit the ball, etc.
In putting it is most important that the ball is hit in such a way that it gets the right initial velocity and direction in order for the ball just to reach the hole. The initial velocity is affected by three conditions: the velocity of the club head as it hits the ball, the effective mass of the putter and the position of the hitting point on the face of the club head.
Given the effective mass of the putter, it is the player's ability to control the velocity of the club head and the hitting point that distinguishes a good putt from a not so good putt. The greatest transmission of energy from club to ball is achieved when the hitting point on the face of the club head is on the course of the centre of gravity of the club head. With minor variations, a good player will place the hitting point correctly, players practicing to get it to be the same from one stroke to the other. To a trained player the greatest challenge is therefore to get the right velocity for the club head, so that the ball gets the right initial velocity.
When putting is performed by wrist rotation, the player grips the club with both hands at the free end of the shaft and holds the club right in front of himself as he is bending forward. By a rotation of the wrists, the club is rotated about an essentially horizontal axis of rotation at the wrists, and the stroke is performed without the back and the shoulder portion moving. When putting is performed by a rotation of the vertebral column, the club is gripped in a way corresponding to that in wrist rotation, but the stroke movement is achieved by a rotation of the upper body about the vertebral column. The club rotates about an essentially horizontal axis at the height of the top of the vertebral column. Experienced golfers prefer to perform a putt by rotation of the vertebral column. Wrist putting is more common among novices.
A putt normally requires very little energy, a small part of a trained player's stroke capacity is involved. More often than not, putts are carried out at a very low club velocity. It is difficult to adjust the transmission of energy in the stroke. To increase the stability of the putter in the stroke, known putters have a light shaft and a relatively heavy club head, and the development has been towards heavier and heavier club heads. The club head of a putter weighs from 250 to 500 grams, whereas the shaft typically weighs from 100 to 120 grams. An increased mass of the club head has a stabilizing effect, but it is still difficult to achieve the right initial velocity on the golf ball. This may be caused by the fact that a heavy club head means an increased active mass transmitting energy to the ball, and even small velocity differences in the moment of striking make noticeable differences in the initial velocity of the ball.